Formation of capillarylike tubular structures in a fibrin-collagen matrix depends on plasmin and MMP activity.

hMVECs were cultured on top of a 3-dimensional matrix fibrin matrix containing 10% collagen in M199 supplemented with 10% HS and 10% NBCS and stimulated with 50 ng/mL VEGF₁₆₅ and 10 ng/mL TNF-α (VEGF/ TNF-α) with or without (no add) the addition of an aprotinin (aprot; 100 U/mL) or BB94 (10 μg/mL). After 4 days of culturing, total tube length was measured as described and expressed as percentage of tube length formed by hMVECs stimulated with VEGF₁₆₅/TNF-α. The data are expressed as mean ± SD of 3 experiments with duplicate wells.